Variable inductance for radio apparatus



April 15, 1924 S. MOLINA VARIABLE INDUCTANCE FOR RADIO APPARATUS Filed Deo. 8.

@El f AQ' AAN/UM er y Afro/MHS vPatented Apr. l5,V 1924. ,l

PATENT OFFICE.

sALvaooa xonriu, or nnw'ronx, n.r.

l 'VARIABLE INDUGTANGE 10B m10 APPARATUS.k

Application mcd December 8, 1928. Serial lo. 605,854.

To all whom it may concern: .L

Be it known that I, SALVADOR MOLINA, a citizen of the United States, and a resident of the city of New York, borough of Manhattan, in the county and State of New York, have invented a new and Improved Variable Inductance for Radio A paratus of which the following is a full, c ear, an exact description.

This invention relates to anew and improved form of variable inductance for use with radio sets and adaptable to use as either a variometer or a variocoupler unit.

It is an object of the invention to provide such a new and improved form of variable inductance that the' following results are accom lished to improve the operation and efficiency of the device 1. A much finer de of tuning can be achieved, because of t e close proximity of the induetively related circuits, this proximity being obtained by reason of the particular form of the inductively related coils.

2. A wider range of tuning, due to the shape of the coils and the arrangement of the unit. l

v3. A finer degree of tuning, due to the fact that the stator windin of the variable inductance can be switche in or out turn by turn instead of every few turns as is ordmaril the case.

4. e construction of this variable inductancedevice permits its use either as a variocoupler or a variometer with the use of substantially the same standard parts for either form.

5. This s ecial construction does away with the te ious and expensive work of assembling the device on the usual 'panelboards, and eliminates soldered connections.

The invention is illustrated in the drawingrs, of whichigure 1 is an elevation of the device with a portion broken away showing the form it assumes when it is used as a variocoupler.

Fig. 2 is a section taken On-the line 2-2 of 1he form of the invention shown inthe drawings is a preferred form, although it is understood that modifications in the construction and arrangement ofthe parts and in the character of the materials used may be adopted without departing from the spirit of the invention.

In view of the fact that a variocoupler and a variometer in most cases differ from each other' only b reason of the im' that the that in other respects the two devices are not unlike, I have devised a construction of variable inductance unit in Whichpractically the same parts, preferably moul ed parts, can be. used to make either a variocoupler or a variometer. In lthis way I considerably reduce the expense of manufacturin these devices, and have'achieved an intero angeability of parts which reduces the expense of repairing. This idea, combined with the particular shape of the fixed aLl movable coils, enables me to produ/ce a sim le, economical device for use as one type o instrument or another, capable of a very fine degree of tuning, and occupying very little space in connection with other apparatus of a wireless set. y 'f? Considering the form shown in Figs. 1 and 2, which is that of a variocoupler, it will be noted that I have provided a fixed fra-me or shell 1 to support the fixed windin of the stator member. This shell is, as wi be Observed from a considera-tion of Fig. 2,

elliptical in cross section, having a l h parallel to the panel board considera lly eater than its depth away from the pane ard. By reason of this shape, I can get a proper length of winding on the frame without extending too deeply awa. from the rear face of the panelboard and t ereby occupy too much space. The shell or stator frame, on its outer with slightly projectlng shoulders 2, 3 and 4 between whlch stator windings 5 and 6 may be disposed. These windings can be placed on the surface of the stator frame 1 between the shoulders 2, 3 and 4 in any desired manner. The windings 5 and 6 disosed on the outer surface of the stator rame are there disposed when the device is to be used as a variocoupler, but when the device is to be used as a variometer, it is desirable to have the coils brought more closely in association with the rotor coils, and to that end I provide a shoulder 7 on the central portion of the stator frame 1, and dispose windings 8 and 9 against'the inner surface of the stator frame 1 with their inner edges bearing against the shoulder 7. In the case of the coils 5 and 6, they may be wound on the outside of the frame in an suitable manner; but in the case of the coi s 8 and 9, they preferably are Ywound on a periphery, is provided v llO form to the proper dimension and then treated with any suitable stiening material to enable them to maintain their form and are then inserted within the\stator frame 1 against the shoulder 7. This stator frame 1 is adapted to be disposed adjacent a suitable anelboard with its greater dimension', name y, its length, parallel to the panelboard, and, as would be the case in most instances, with its major axisdisposed vertically. To that end I provide bracket plates and 11 disposed on and suitably i attached to the front surface of the stator frame 1 at opposite ends thereof; and I also provide a similar pair of plates connected to the rear surface of the frame, so that I have four bracket plates connected to the lower corners of the frame to support it, either from the bottom of the box or to suplrt it against the vertical panelboard wa Ifhese bracket plates are spaced apart by a pair of shafts or spacing bars 12 and 13. These spacing bars are engaged by clamping nuts 14.- and l5 surrounded between the plates by insulating sleeves such as 16.

The bracket plates 10 and 11 at the front and the rear are provided with upturned flanges 22 suitably apertured either to `receive binding posts 21 or to receive screws, which fasten these flan s against the panelboards or. other suitab e stock.

The upper front portion of the fixed stator frame 1 is engaged by a bracket plate 23 having an overturned flange portion 24 to be en vged with the panelboard and also adaptabea to carry a binding post 25. This bracket plate member 23 is apertured at its lower end to receive a shaft 27 having an enlarged portion 28 passing through the stator frame and the panelboard. A shaft 29, having an enlarged insulatin portion or sleeve 30 thereon, passes throug the opposite side of the stator frame and also through the rotatable member 33 disposed within the fixed stator frame 1. The outer end of the shaft 28 is rovided with a hand knob 31 and a dial p ate 32 adapted to bey lroved over the front surface of the panelar The rotor 33 disposed within the stator is likewise elliptical in cross section, although its outer surface, as shown in Fig. 1, is curved and rovided with a central projection or sho der 34, on either side of which rotor windings 35 and 36 are disposed. These windings are held between the shoulder 34 and the end shoulders 37 and 38.

This elliptically shaped rotor` can be disposed very close to the stator and be capable of receiving a suilicient number of turns of winding and yet occupy a small amount of space back of the panelboard, especially in depth. It will, therefore, be seen that great er elciency in the inductance eld can be obtained due to the close proximity of both surfaces; that a wider range of tuning can be effected due to the particular shape of the coil; that the tuning of the primary or` sta-tor coil can be made turn by turn or wire by wire, whereby a finer degree of tuning is obtained and the use of a variable condenser is eliminated. Because the switch arms vary the number of turns of the stator in circuit, the use of taps or contact members in the panelboard is eliminated and the formation of soldered connections to said ta s is also done away with, and the necessity or drilling holes in the switch or panelboard for these contact points is done away with. In the panelboard there are only three holes to drill, one for the rotor shaft and two for the shafts of the switch arms' 17 and 18, and these latter only in the event that the device is to be used as a variocoupler. Substantially all the moulded parts of one device can be used in the construction of the other.

What I claim is A variable inductance device which includes a stator frame, bracket plates supporting` said frame at the front and rear thereof. spacer bars extending between said plates from the front to the rear, windings on the outside of said frame, switch arms contacting with the windings and mounted on the spacer bars, and manually operable means connected to said bars to rotate said bars and the switch arm across the windings.

SALVADOR MOLINA. 

